Perform assays to evaluate and characterize the humoral immune responses of animals immunized with HIV or SIV vaccines and/or infected with HIV, SHIV, or SIV Perform ELISA, western blot or other assays to detect the presence of SIV antibodies in sera or mucosal secretions of immunized and/or infected animals Determine the capability of sera (or mucosal secretions) from animals immunized with SIV vaccines, or infected with SIV, to neutralize infection of cell lines and/or primary cells (PBMC) by the SIV strain used for the vaccine. Further characterize these antibodies, including determining the neutralization titer against the vaccine (homologous) SIV strain. Determine the neutralization titer against infection of appropriate cell lines and/or PBMC by a heterologous strain or strains of SIV for sera (or mucosal secretions) that were determined (above) to neutralize the homologous strain of SIV. Grow appropriate HIV, SHIV, and SIV virus stocks, determine the in vitro titer of the stocks, and demonstrate that the viruses can be neutralized by sera from HIV-infected people or SHIV- or SIV-infected monkeys prior to conducting neutralization assays with the sera from the vaccine studies Perform assays to evaluate and characterize immune responses at mucosal sites in nonhuman primates immunized with HIV or SIV vaccines and/or infected with HIV, SHIV, or SIV. a. Perform assays to detect and measure HIV-specific or SIV-specific antibodies (IgG, IgA, and secretory IgA antibodies) or antibody-secreting cells in mucosal secretions such as vaginal and rectal swabs/washes and saliva of immunized and/or infected macaques. Include assays on appropriate negative control samples. b. Develop and conduct assays to evaluate functional humoral immune responses (such as virus neutralization assays as described above) in mucosal secretions or mucosal tissues from immunized and/or infected macaques.